Intermittent Oxygen Inhalation with Proper Frequency Improves Overall Health Conditions and Alleviates Symptoms in a Population at High Risk of Chronic Mountain Sickness with Severe Symptoms.

BACKGROUND: Oxygen inhalation therapy is essential for the treatment of patients with chronic mountain sickness (CMS), but the efficacy of oxygen inhalation for populations at high risk of CMS remains unknown. This research investigated whether oxygen inhalation therapy benefits populations at high risk of CMS. METHODS: A total of 296 local residents living at an altitude of 3658 m were included; of which these were 25 diagnosed cases of CMS, 8 cases dropped out of the study, and 263 cases were included in the analysis. The subjects were divided into high-risk (180 ≤ hemoglobin (Hb) <210 g/L, n = 161) and low-risk (Hb <180 g/L, n = 102) groups, and the cases in each group were divided into severe symptom (CMS score ≥6) and mild symptom (CMS score 0-5) subgroups. Severe symptomatic population of either high- or low-risk CMS was randomly assigned to no oxygen intake group (A group) or oxygen intake 7 times/week group (D group); mild symptomatic population of either high- or low-risk CMS was randomly assigned to no oxygen intake group (A group), oxygen intake 2 times/week group (B group), and 4 times/week group (C group). The courses for oxygen intake were all 30 days. The CMS symptoms, sleep quality, physiological biomarkers, biochemical markers, etc., were recorded on the day before oxygen intake, on the 15th and 30th days of oxygen intake, and on the 15th day after terminating oxygen intake therapy. RESULTS: A total of 263 residents were finally included in the analysis. Among these high-altitude residents, CMS symptom scores decreased for oxygen inhalation methods B, C, and D at 15 and 30 days after oxygen intake and 15 days after termination, including dyspnea, palpitation, and headache index, compared to those before oxygen intake (B group: Z = 5.604, 5.092, 5.741; C group: Z = 4.155, 4.068, 4.809; D group: Z = 6.021, 6.196, 5.331, at the 3 time points respectively; all P < 0.05/3 vs. before intake). However, dyspnea/palpitation (A group: Z = 5.003, 5.428, 5.493, both P < 0.05/3 vs. before intake) and headache (A group: Z = 4.263, 3.890, 4.040, both P < 0.05/3 vs. before intake) index decreased significantly also for oxygen inhalation method A at all the 3 time points. Cyanosis index decreased significantly 30 days after oxygen intake only in the group of participants administered the D method (Z = 2.701, P = 0.007). Tinnitus index decreased significantly in group A and D at 15 days (A group: Z = 3.377, P = 0.001, D group: Z = 3.150, P = 0.002), 30 days after oxygen intake (A group: Z = 2.836, P = 0.005, D group: Z = 5.963, P < 0.0001) and 15 days after termination (A group: Z = 2.734, P = 0.006, D group: Z = 4.049, P = 0.0001), and decreased significantly in the group B and C at 15 days after termination (B group: Z = 2.611, P = 0.009; C group: Z = 3.302, P = 0.001). In the population at high risk of CMS with severe symptoms, oxygen intake 7 times/week significantly improved total symptom scores of severe symptoms at 15 days (4 [2, 5] vs. 5.5 [4, 7], Z = 2.890, P = 0.005) and 30 days (3 [1, 5] vs. 5.5 [2, 7], Z = 3.270, P = 0.001) after oxygen intake compared to no oxygen intake. In the population at high risk of CMS with mild symptoms, compared to no oxygen intake, oxygen intake 2 or 4 times/week did not improve the total symptom scores at 15 days (2 [1, 3], 3 [1, 4] vs. 3 [1.5, 5]; χ2 = 2.490, P = 0.288), and at 30 days (2 [0, 4], 2 [1, 4.5] vs. 3 [2, 5]; χ2 = 3.730, P = 0.155) after oxygen intake. In the population at low risk of CMS, oxygen intake did not significantly change the white cell count and red cell count compared to no oxygen intake, neither in the severe symptomatic population nor in the mild symptomatic population. CONCLUSIONS: Intermittent oxygen inhalation with proper frequency might alleviate symptoms in residents at high altitude by improving their overall health conditions. Administration of oxygen inhalation therapy 2-4 times/week might not benefit populations at high risk of CMS with mild CMS symptoms while administration of therapy 7 times/week might benefit those with severe symptoms. Oxygen inhalation therapy is not recommended for low-risk CMS populations.

Astragalus on the anti-fatigue effect in hypoxic mice.

OBJECTIVE: Astragalus is a traditional Chinese medicine to improve the function of the body. The purpose of this study is to investigate the effect of astragalus on improvement of anti-fatigue capacity in mice under simulated plateau environment. METHODS: Male Kunming mice were randomly divided into the following groups: the control group, astragalus treatment groups in low dosage (LD) (1.0 g/kg·d), mid dosage (MD) (3.0 g/kg·d), and high dosage (HD) (30 g/kg·d). The control group were fed under normoxia environment, and hypoxic mice were fed at a stimulated elevation of 5000 meters. After continuous intragastric administration for 10 days, exhaustive swimming experiment was conducted in the anoxic environment. The swimming time, glucose and lactic acid concentration in blood, glycogen contents in liver, SOD and MDA were determined. RESULTS: Compared with the control group, the swimming time of each astragalus treated group was evidently prolonged (P < 0.05), and the area under the blood lactic acid curve was significantly decreased (P < 0.05). In the high and middle dose of astragalus group, liver glycogen was obviously increased. After exhausted swimming, glycogen contents in blood and SOD were significantly increased, while MDA was evidently reduced (P < 0.05). CONCLUSION: Astragalus can alleviate physical fatigue in mice under simulated plateau environment. It has an obvious anti-fatigue effect and it's worthy of further study.

Th2 lymphocytes migrating to the bone marrow under high-altitude hypoxia promote erythropoiesis via activin A and interleukin-9.

The mechanism of accelerated erythropoiesis under the hypoxic conditions of high altitude (HA) remains largely obscure. Here, we investigated the potential role of bone marrow (BM) T cells in the increased production of erythrocytes at HA. We found that mice exposed to a simulated altitude of 6,000 m for 1-3 weeks exhibited a significant expansion of BM CD4+ cells, mainly caused by increasing T helper 2 (Th2) cells. Using a coculture model of BM T cells and hematopoietic stem/progenitor cells, we observed that BM CD4+ cells from hypoxic mice induced erythroid output more easily, in agreement with the erythroid-enhancing effect observed for Th2-condition-cultured BM CD4+ cells. It was further demonstrated that elevated secretion of activin A and interleukin-9 by BM Th2 cells of hypoxic mice promoted erythroid differentiation of hematopoietic stem/progenitor cells and the growth of erythroblasts, respectively. Our study also provided evidence that the CXCL12-CXCR4 interaction played an important role in Th2 cell trafficking to the BM under HA conditions. These results collectively suggest that Th2 cells migrating to the BM during HA exposure have a regulatory role in erythropoiesis, which provides new insight into the mechanism of high altitude polycythemia.

Exposure to di(n-butyl)phthalate and benzo(a)pyrene alters IL-1ß secretion and subset expression of testicular macrophages, resulting in decreased testosterone production in rats.

Di(n-butyl)phthalate (DBP) and benzo(a)pyrene (BaP) are environmental endocrine disruptors that are potentially hazardous to humans. These chemicals affect testicular macrophage immuno-endocrine function and testosterone production. However, the underlying mechanisms for these effects are not fully understood. It is well known that interleukin-1 beta (IL-1ß), which is secreted by testicular macrophages, plays a trigger role in regulating Leydig cell steroidogenesis. The purpose of this study was to reveal the effects of co-exposure to DBP and BaP on testicular macrophage subset expression, IL-1ß secretion and testosterone production. Adult male Sprague-Dawley rats were randomly divided into seven groups; two groups received DBP plus BaP (DBP+BaP: 50+1 or 250+5mg/kg/day) four groups received DBP or BaP alone (DBP: 50 or 250 mg/kg/day; BaP: 1 or 5mg/kg/day), and one group received vehicle alone (control). After co-exposure for 90 days, the relative expression of macrophage subsets and their functions changed. ED2(+) testicular macrophages (reactive with a differentiation-related antigen present on the resident macrophages) were activated and IL-1ß secretion was enhanced. DBP and BaP acted additively, as demonstrated by greater IL-1ß secretion relative to each compound alone. These observations suggest that exposure to DBP plus BaP exerted greater suppression on testosterone production compared with each compound alone. The altered balance in the subsets of testicular macrophages and the enhanced ability of resident testicular macrophages to secrete IL-1ß, resulted in enhanced production of IL-1ß as a potent steroidogenesis repressor. This may represent an important mechanism by which DBP and BaP repress steroidogenesis.